Mike Stevenson

A vision specific functional index for use in patients with age related macular degeneration

AIM To develop and evaluate a new vision specific functional index for use in individuals with age related macular degeneration (AMD). METHODS Following consultation with patients with AMD and healthcare professionals, a questionnaire entitled the Daily Living Tasks Dependent on Vision (DLTV) was constructed. It was administered by interview to three separate groups of individuals aged 50 years or older: people with AMD, people with cataract, and people with no visual disability. The relations between DLTV, distance visual acuity, and disorder were examined using Pearson’s product moment correlation coefficients, stepwise regression, and principal component analysis. RESULTS There was a positive correlation between DLTV items and distance visual acuity in the better eye. Principal component analysis showed that the DLTV has a major single dimension within it. This first principal component accounted for 59% of the variation and correlated well with distance visual acuity in the better eye. Other components were found, one of which correlated with the difference in vision in the two eyes and one which featured in the differentiation of AMD subjects from individuals with cataracts. CONCLUSIONS The DLTV provided information on visual impairment in patients over and above that obtained from a measure of visual acuity. It also showed that patients with AMD experience greater difficulty with daily living tasks for any given level of acuity than do patients with cataract.

Age-related changes in energy efficiency of gait, activity, and participation in children with cerebral palsy

Aim  The aim of this study was to use a prospective longitudinal study to describe age‐related trends in energy efficiency during gait, activity, and participation in ambulatory children with cerebral palsy (CP).

Energy efficiency in gait, activity, participation, and health status in children with cerebral palsy

The aim of the study was to establish if a relationship exists between the energy efficiency of gait, and measures of activity limitation, participation restriction, and health status in a representative sample of children with cerebral palsy (CP). Secondary aims were to investigate potential differences between clinical subtypes and gross motor classification, and to explore other relationships between the measures under investigation. A longitudinal study of a representative sample of 184 children with ambulant CP was conducted (112 males, 72 females; 94 had unilateral spastic C P, 84 had bilateral spastic C P, and six had non‐spastic forms; age range 4‐17y; Gross Motor Function Classification System Level I, n=57; Level II, n=91; Level III, n=22; and Level IV, n=14); energy efficiency (oxygen cost) during gait, activity limitation, participation restriction, and health status were recorded. Energy efficiency during gait was shown to correlate significantly with activity limitations; no relationship between energy efficiency during gait was found with either participation restriction or health status. With the exception of psychosocial health, all other measures showed significant differences by clinical subtype and gross motor classification. The energy efficiency of walking is not reflective of participation restriction or health status. Thus, therapies leading to improved energy efficiency may not necessarily lead to improved participation or general health.

Identification of lesion components that influence visual function in age related macular degeneration

Aims: To explore the relation between lesion composition as assessed by fundus photography and fluorescein angiography with clinical measures of vision in eyes of patients with age related macular degeneration (AMD). Methods: A standardised visual function assessment along with colour stereo pair fundus photography was carried out in both eyes of 58 subjects with a confirmed clinical diagnosis of AMD. The size, location, and composition of the macular lesion (blood, exudate, subretinal fluid, pigment, membrane, atrophy, and fibrosis) were measured on the colour photographs using computer assisted image analysis. Of the 58 subjects, 44 also had concurrent fluorescein angiography. Classic and occult choroidal neovascularisation (CNV), blood, blocked fluorescence, fibrosis, geographic atrophy, and the total area of abnormal fluorescence were measured. Multiple linear regression was used to examine the relation between clinical measures of vision and the location and extent of lesion components identified by both colour and fluorescein image capture. Results: The composition of the macular lesion strongly influenced visual function, with atrophy (p=0.001) and fibrosis (p=0.002) accounting for most of the variation. When the location of the lesion with respect to the fovea was examined, fibrosis within the fovea significantly influenced all clinical measures of vision (p=0.008). The regression model selected the total area of abnormal fluorescence and a composite parameter (a semiquantitative measure of the following characteristics: atrophy, exudates, blood, and fibrosis ) from colour photography (r2 =0.52) as the variables that explained most of the variation in clinical measures of vision. Conclusions: The composition and extent of the macular lesion strongly influences visual function in eyes with AMD. Both colour photography and angiography yielded information, which together explained considerably more of the variation in the clinical measures of vision than either on its own.

Test-retest reliability of a 1-min walk test in children with bilateral spastic cerebral palsy (BSCP).

The test-retest reliability of a 1-min walk test at a childs maximum walking speed was assessed in children with bilateral spastic cerebral palsy (BSCP). Twelve male and five female children (age range 3-18 years, mean age 12 years 8 months) participated in the study. Children were classified as GMFCS level I (n=5), level II (n=8) and level III (n=4). Results showed that for walk tests performed on different days, distances varied by no more than 13.1m (for 95% of participants) and that a practice walk was vital for reducing systematic bias. The intraclass correlation coefficient was 0.94. A 1-min walk test is a reliable method of assessing function in children with CP but care must be taken when interpreting changes in individual patient data.

Further validation of the Daily Living Tasks Dependent on vision : identification of domains

Aim: To examine the Daily Living Tasks Dependent on Vision (DLTV), a visual function questionnaire for domain structure, and redundancy. Method: 235 subjects underwent full ophthalmic assessment and completed the DLTV questionnaire by interview. Principal component analysis with varimax rotation and item response theory (IRT) were used to assign the items to domains. The internal consistency of each domain was examined using Cronbach’s alpha. Redundancy was assessed by regressing each item in a domain against the remainder of items in that domain. Results: Four domains were identified. Domain 1 was formed by nine items, which after applying IRT were seen to be among the most difficult questions in the instrument. Domain 2 contained eight items, all of which fell in the easier half of the instrument on applying IRT. Domain 3 contained only three items, all of which were among the easier questions and appear to deal with peripheral vision function. Domain 4 consisted of two items dealing with adaptation to light and dark conditions. Cronbach’s alpha for each domain was 0.96, 0.93, 0.73, 0.66. Redundancy was found to be present in domain 1, which was therefore reduced by two items, with little effect on internal consistency. Conclusions: The authors believe using the domains identified in this report will optimise the information provided by patients on their ability to function on visually demanding tasks.

A Retrospective Comparison of Craniofacial Form in Northern Irish Children with Unilateral Cleft Lip and Palate

OBJECTIVE This study evaluated the craniofacial form of a sample of Northern Irish children with unilateral cleft lip and palate (UCLP). The quality of the outcomes achieved was compared with the outcomes reported for the six centers involved in the European multicenter study (Mars et al., 1992; Mølsted et al, 1992). DESIGN Retrospective analysis. PATIENTS All children born with complete skeletal UCLP in Northern Ireland during the years 1983 to 1987. MAIN OUTCOME MEASURES Cephalometric analysis was used to determine the craniofacial form and soft tissue profile. The quality of the dental arch relationships was independently assessed using the Goslon ranking system. RESULTS The sample comprised 25 children with complete skeletal UCLP who had cephalometric radiographs and study casts recorded at a mean age of 9.4 years (range, 8 to 11 years). Cephalometric analysis revealed no important skeletal differences between the Northern Irish UCLP children and the published results from the six Eurocleft centers. The soft tissue profile of the Northern Irish UCLP children was significantly more convex than the soft tissue profile recorded for center D in the Eurocleft study. The Goslon ranking system revealed that 18 (72%) of the Northern Irish UCLP children had good or satisfactory dental arch relationships. CONCLUSIONS No clinically important differences were detected between the mean cephalometric skeletal parameters of the Northern Irish UCLP children and those published for the six cleft centers involved in the Eurocleft study. On average, the Northern Irish UCLP children were found to differ significantly from Euroclefts center D in their soft tissue facial contour and sagittal lip profile. The quality of the dental arch relationships of the Northern Irish sample was between the best and the less good Eurocleft centers.

Predictors of outcome among patients with Class II Division 1 malocclusion treated with fixed appliances in the permanent dentition

This retrospective study investigated the outcomes achieved in 212 consecutively completed patients with Class II Division 1 malocclusion (overjet > 6 mm). All patients were treated in the permanent dentition with upper and lower fixed appliances. A composite outcome measure was used to identify those cases with an excellent outcome (posttreatment PAR </= 5, posttreatment upper incisor to maxillary plane angle between 104.7 degrees and 115.3 degrees, and anterior movement of the lower incisors </= 2 mm). Logistic regression analysis with patient group as the dependent variable was used to evaluate the predictive value of 32 patient and treatment variables. The three outcome measures (posttreatment PAR score, posttreatment upper incisor inclination, and anterior movement of lower incisors) were ranked and combined to form a single continuous outcome variable. This was used as the dependent variable to carry out further analysis with the linear regression method. Both methods of analysis identified pretreatment overjet and pretreatment upper incisor inclination as significant predictors of outcome. The results revealed that in patients with large overjets an excellent outcome can only be predicted if the upper incisors are very proclined. Every 2 mm increase in overjet (above 4 mm) required approximately a 5 degrees increase in incisor proclination to achieve an excellent outcome.

A Pilot Study of a Low-Tilt Biphasic Waveform for Transvenous Cardioversion of Atrial Fibrillation: Improved Efficacy Compared with Conventional Capacitor-Based Waveforms in Patients

Background: The optimal waveform tilt for defibrillation is not known. Most modern defibrillators used for the cardioversion of atrial fibrillation (AF) employ high‐tilt, capacitor‐based biphasic waveforms.

Lithium usage and renal function testing in a large UK community population; a case–control study ☆ ☆☆ ★ ★★

OBJECTIVE This study investigates the prevalence of lithium use, monitoring practice and associated effects on renal function in a large UK community sample. METHOD A large population-based renal function database was cross-referenced with a general practitioner database of 404,673 patients. The renal function of patients prescribed lithium during the 2-year period was compared with that of matched controls. The renal monitoring patterns of these cases were investigated in a naturalistic observational study. Data underwent parametric testing - continuous variables by analysis of variance, with appropriate adjustment, and categorical outcomes by χ(2) testing. Block analysis of variance was undertaken on case-control data. RESULTS A total of 422 patients in the database were prescribed lithium. Renal function monitoring in accordance with published guidelines occurred in 69% of patients. Patients taking lithium had a significantly higher serum creatinine (5.8 μmol/L, P<.001) and lower glomerular filtration rate (5.9 ml/min, P<.001) when compared to matched controls. CONCLUSIONS This is the first study carried out in a large community sample. Lithium remains widely prescribed in the community setting. The study confirms that lithium has a statistically and clinically significant negative effect on renal function. Despite published guidelines and recognition of the importance of serial measurements, monitoring of renal function is inconsistent.